JP2011173295A - Relief printing plate original plate for laser engraving and method for manufacturing the same, and relief printing plate and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a relief printing plate original plate for laser engraving capable of obtaining the relief printing plate original plate for laser engraving excellent in adhesiveness and the plane property of a plate surface, a method of manufacturing a relief printing plate with the usage of the relief printing plate original plate for laser engraving manufactured by the manufacturing method, and the relief printing plate manufactured by the method. <P>SOLUTION: The method of manufacturing the relief printing plate original plate for laser engraving includes a layer forming process for forming a recording layer on a base material, a pasting process for pasting a supporting body on a surface confronting a base material side surface in the layer forming process of the recording layer by applying a photo-curable adhesive, and a bonding process for bonding the recording layer and the supporting body by curing the photo-curable adhesive by light. The photo-curable adhesive contains a (meth)acrylate compound having a hydroxyl group, a (meth)acrylate compound having no hydroxyl group, and a photopolymerization initiator. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a relief printing plate precursor for laser engraving and a production method thereof, and a relief printing plate and a plate making method thereof.

As a method of forming a printing plate by forming irregularities on the photosensitive resin layer laminated on the support surface, the recording layer formed using the photosensitive composition is exposed with ultraviolet light through the original film, A method of selectively curing an image portion and removing an uncured portion with a developer, so-called “analog plate making” is well known.
The relief printing plate is a relief printing plate having a relief layer having irregularities, and the relief layer having such irregularities includes, for example, an elastomeric polymer such as synthetic rubber, a resin such as a thermoplastic resin, Alternatively, it is obtained by patterning a recording layer containing a photosensitive composition containing a mixture of a resin and a plasticizer to form irregularities. Of such relief printing plates, those having a soft relief layer are sometimes referred to as flexographic plates.
When producing a relief printing plate by analog plate making, since an original image film using a silver salt material is generally required, the production time and cost of the original image film are required. Furthermore, since chemical processing is required for development of the original image film and processing of the development waste liquid is also required, a simpler plate preparation method, for example, a method that does not use the original image film, and development processing are required. The method of not doing is examined.

In recent years, a method of making a recording layer by scanning exposure without using an original film has been studied.
As a technique that does not require an original film, a relief printing plate precursor having a laser-sensitive mask layer element capable of forming an image mask on a recording layer has been proposed (see, for example, Patent Documents 1 and 2). According to these plate making methods, since an image mask having the same function as the original film is formed from the mask layer element by laser irradiation based on the image data, it is referred to as “mask CTP method”. A film is not necessary, but the subsequent plate making process is a process of exposing with ultraviolet light through an image mask to develop and remove an uncured portion, and there is still room for improvement in that a development process is required.

Many so-called “direct engraving CTP methods” have been proposed as plate making methods that do not require a development step, in which a recording layer is directly engraved by laser to make a plate. The direct engraving CTP method literally engraves with a laser to form reliefs, and has the advantage that the relief shape can be freely controlled, unlike the relief formation using the original film. For this reason, when an image such as a letter is formed, the area is engraved deeper than other areas, or the fine halftone dot image is engraved with a shoulder in consideration of resistance to printing pressure, etc. Is also possible.
Regarding the plate material that has been used in the direct engraving CTP method so far, a hydrophobic elastomer (rubber) is used as a binder that determines the properties of the plate material (for example, see Patent Documents 1 to 6), and hydrophilicity. Many products using the polyvinyl alcohol derivative (see, for example, Patent Document 7) have been proposed.

US Pat. No. 5,798,202 US Patent Application Publication No. 2008/0061036 Japanese Patent Laid-Open No. 2002-3665 Japanese Patent No. 3438404 JP 2004-262135 A JP 2001-121833 A JP 2006-2061 A

  An object of the present invention is to provide a method for producing a relief printing plate precursor for laser engraving capable of obtaining a relief printing plate precursor for laser engraving having excellent adhesion and flatness of the plate surface, and for laser engraving obtained by the production method. It is to provide a plate making method of a relief printing plate using a relief printing plate precursor and a relief printing plate obtained thereby.

The above-described problems of the present invention have been solved by the means described in <1>, <10>, <11> and <13> below. It is described below together with <2> to <9> and <12> which are preferred embodiments.
<1> A layer forming step for forming a recording layer on a base material, and a bonding method in which a photocurable adhesive is applied to the surface of the recording layer facing the base material side in the layer forming step and bonded to a support. A step, and an adhesive step of curing the photocurable adhesive with light to adhere the recording layer and the support, wherein the photocurable adhesive has a hydroxyl group (meth) acrylate compound, A method for producing a relief printing plate precursor for laser engraving, comprising a (meth) acrylate compound having no hydroxyl group, and a photopolymerization initiator,
<2> The method for producing a relief printing plate precursor for laser engraving according to <1>, wherein the recording layer has a thickness of 0.5 to 10 mm,
<3> The above-mentioned <1> or <2>, wherein the photocurable adhesive is composed only of a hydroxyl group-containing (meth) acrylate compound, a hydroxyl group-free (meth) acrylate compound, and a photopolymerization initiator. Manufacturing method of relief printing plate precursor for laser engraving
<4> For laser engraving according to any one of the above items <1> to <3>, including a protective step of forming a peelable protective layer on the substrate side surface in the layer forming step of the recording layer. Manufacturing method of relief printing plate precursor,
<5> The method for producing a relief printing plate precursor for laser engraving according to any one of the above <1> to <4>, wherein the recording layer contains a binder polymer and a photothermal conversion agent,
<6> The method for producing a relief printing plate precursor for laser engraving according to <5>, wherein the photothermal conversion agent contains carbon black,
<7> The method for producing a relief printing plate precursor for laser engraving according to any one of the above <1> to <6>, wherein the recording layer has a siloxane bond,
<8> The above <1> to <1>, wherein the layer forming step is a step of forming a recording layer comprising a resin composition containing a binder polymer, a photothermal conversion agent, and a reactive silane compound on a substrate. 7> The method for producing a relief printing plate precursor for laser engraving according to any one of 7>,
<9> The method for producing a relief printing plate precursor for laser engraving according to the above <8>, comprising a crosslinking step of thermally crosslinking the recording layer between the layer forming step and the bonding step,
<10> A relief printing plate precursor for laser engraving, obtained by the production method according to any one of <1> to <9> above,
<11> A engraving step of forming a relief layer by laser engraving the recording layer of the relief printing plate precursor for laser engraving obtained by the production method according to any one of <1> to <9> above A method for making a relief printing plate,
<12> In the engraving step, engraving with a fiber-coupled semiconductor laser having a wavelength of 700 to 1,300 nm, the method for making a relief printing plate according to <11> above,
<13> A relief printing plate having a relief layer produced by the plate making method of a relief printing plate according to <11> or <12>.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the relief printing plate precursor for laser engraving which can obtain the relief printing plate precursor for laser engraving which is excellent in adhesiveness and the flatness of a plate surface, for laser engraving obtained by the said manufacturing method A method for making a relief printing plate using the relief printing plate precursor, and a relief printing plate obtained thereby were provided.

It is the schematic which shows an example of the manufacturing apparatus used for the manufacturing method of the relief printing plate precursor of this invention. It is a schematic diagram which shows the evaluation method of curl evaluation.

  Hereinafter, the present invention will be described in detail.

(Manufacturing method of relief printing plate precursor for laser engraving)
The method for producing a relief printing plate precursor for laser engraving of the present invention (hereinafter also simply referred to as “relief printing plate precursor”) includes a layer forming step of forming a recording layer on a substrate, and the layer forming step of the recording layer. A bonding step in which a photocurable adhesive is applied to a surface opposite to the substrate side surface of the substrate and bonded to a support; and the recording layer and the support are cured by curing the photocurable adhesive with light. The photocurable adhesive contains a (meth) acrylate compound having a hydroxyl group, a (meth) acrylate compound not having a hydroxyl group, and a photopolymerization initiator. .
That is, according to the method for producing a relief printing plate precursor for laser engraving of the present invention, a recording layer is formed on a substrate, and a specific light is applied to a surface facing the substrate side surface of the recording layer, a so-called air surface. It is a method including at least a step of applying a curable adhesive and bonding it to a support, and curing and bonding the photocurable adhesive with light.
In the relief printing plate precursor obtained by the method for producing a relief printing plate precursor of the present invention, the surface of the recording layer on the substrate side in the layer forming step becomes a drawing surface on which laser engraving is performed.
The relief printing plate precursor for laser engraving of the present invention is a relief printing plate precursor for laser engraving obtained by the method for producing a relief printing plate precursor for laser engraving of the present invention.

<Layer formation process>
The method for producing a relief printing plate precursor according to the invention includes a layer forming step of forming a recording layer on a substrate.
There is no restriction | limiting in particular in the base material in the said layer formation process, A well-known base material can be used.
The shape of the base material may be a sheet shape, a belt shape, or a plate shape, and is not particularly limited, but is preferably a belt shape. The material of the base material is not particularly limited, and may be a known material such as resin, rubber, metal or the like.
In the layer forming step, the base material and the recording layer may be in direct contact with each other or may not have direct contact with each other, for example, there may be another layer such as a protective layer between the base material and the recording layer. Good, but preferably in direct contact. By directly contacting the base material and the recording layer, the drawing surface of the recording layer can be changed to a desired surface shape corresponding to the surface shape of the base material, if necessary.
In addition, when the substrate is in direct contact with the recording layer, the surface of the substrate in contact with the recording layer is preferably flat.

The recording layer in the present invention is not particularly limited, and a known layer can be used, and is a layer made of a resin composition for laser engraving described later or a layer obtained by curing a resin composition for laser engraving described later. It is preferable. The recording layer preferably has a crosslinked structure, and is preferably a layer crosslinked by heat and / or light.
In the layer forming step, the method for forming the recording layer on the substrate is not particularly limited, but a resin composition for laser engraving is prepared, and if necessary, a solvent is removed from the resin composition for relief engraving. Preferably, after removal, a method of melt extrusion on a substrate and a method of casting a resin composition on a substrate and removing at least a part of the solvent in the resin composition to form a recording layer can be exemplified, More preferred examples include a method of casting a resin composition on a substrate and removing at least a part of the solvent in the resin composition to form a recording layer.
The resin composition for laser engraving can be produced, for example, by dissolving a crosslinking agent, a binder polymer, and optional components such as a photothermal conversion agent, a fragrance, and a plasticizer in a suitable solvent. Since most of the solvent components need to be removed at the stage of producing the relief printing plate precursor, the solvent is a low-molecular alcohol that easily volatilizes (eg, methanol, ethanol, n-propanol, isopropanol, propylene glycol monomethyl ether). It is preferable to keep the total amount of solvent added as small as possible by adjusting the temperature.
As the resin composition for laser engraving, those described later can be preferably used.
The thickness of the recording layer in the relief printing plate precursor for laser engraving is preferably from 0.05 mm to 20 mm, more preferably from 0.5 mm to 10 mm, still more preferably from 0.5 mm to 7 mm, before and after crosslinking. Particularly preferred is 5 mm or more and 3 mm or less.

The recording layer in the relief printing plate precursor of the present invention preferably has a cross-linked structure from the viewpoint of laser engraving properties, and from the viewpoint of ease of handling and the like, in the stage before the pasting step, More preferably, it has a crosslinked structure.
The method for producing a relief printing plate precursor according to the invention preferably includes a crosslinking step of crosslinking the recording layer with light and / or heat, and from the viewpoint of ease of handling, etc., at the stage before the bonding step. More preferably, the crosslinking step is included.
The method for producing a relief printing plate precursor according to the present invention includes a layer forming step of casting a resin composition for laser engraving on a substrate to form a recording layer, and between the layer forming step and the laminating step. In addition, it is preferable to include a crosslinking step of thermally crosslinking the recording layer. By crosslinking the recording layer, there is an advantage that the relief formed first after laser engraving becomes sharp, and secondly, the adhesiveness of engraving residue generated during laser engraving is suppressed.
The cross-linking is preferably performed by light and / or heat.
Examples of light include visible light, ultraviolet light, and electron beam, but ultraviolet light is most preferable. Further, it is preferable that the light irradiation is performed on the entire surface of the recording layer. In the cross-linking by light, if the support side of the recording layer is the back side, it is only necessary to irradiate the surface. However, if the support is a transparent film that transmits light, the back side can also be irradiated from the back side. preferable. When the protective film exists, the irradiation from the surface may be performed while the protective film is provided, or may be performed after the protective film is peeled off. If there is a possibility that the crosslinking reaction may be inhibited in the presence of oxygen, the recording layer may be covered with a vinyl chloride sheet and evacuated and then irradiated with light. A known light source can be used for light irradiation.
Examples of the heating means for crosslinking by heat include a method of heating the printing plate precursor in a hot air oven or a far infrared oven for a predetermined time, and a method of contacting a heated roll for a predetermined time.
As a method for cross-linking the recording layer in the cross-linking step, thermal cross-linking is preferable from the viewpoint that the recording layer can be uniformly cured (cross-linked) from the surface to the inside.

<Bonding process>
The method for producing a relief printing plate precursor for laser engraving of the present invention is a bonding step in which a photocurable adhesive is applied to the surface of the recording layer facing the substrate side in the layer forming step, and is bonded to a support. including.
Moreover, the said photocurable adhesive agent contains the (meth) acrylate compound which has a hydroxyl group, the (meth) acrylate compound which does not have a hydroxyl group, and a photoinitiator.
The photocurable adhesive may contain a known additive other than the above, but preferably does not contain a volatile organic compound (VOC) having no ethylenically unsaturated group such as an organic solvent, More preferably, it consists only of a (meth) acrylate compound having a hydroxyl group, a (meth) acrylate compound not having a hydroxyl group, and a photopolymerization initiator.
In the bonding step, it is important to apply a specific photocurable adhesive to the surface of the recording layer facing the substrate side in the layer forming step, so-called air surface. By taking the said aspect, the relief printing plate precursor excellent in adhesiveness and film thickness uniformity is obtained.
There is no restriction | limiting in particular as a method to provide a photocurable adhesive agent to the said recording layer in the said bonding process, It can carry out by a well-known method.
Moreover, there is no restriction | limiting in particular as a method of bonding the recording layer and support body in the said bonding process, It can carry out by a well-known method.

[Support]
The material used for the support of the relief printing plate precursor for laser engraving is not particularly limited, but materials having high dimensional stability are preferably used. For example, metals such as steel, stainless steel and aluminum, polyester (for example, PET (polyethylene terephthalate)) , Plastic resins such as PBT (polybutylene terephthalate), PAN (polyacrylonitrile)) and polyvinyl chloride, synthetic rubbers such as styrene-butadiene rubber, and plastic resins reinforced with glass fibers (such as epoxy resins and phenol resins) It is done. As the support, a PET film or a steel substrate is preferably used. Among these, a transparent support is preferable, and a PET film is more preferable.

[(Meth) acrylate compound having a hydroxyl group]
The photocurable adhesive contains a (meth) acrylate compound having a hydroxyl group.
The (meth) acrylate compound having a hydroxyl group is not particularly limited as long as it has at least a hydroxyl group (hydroxy group) and a (meth) acryloyl group, but is a monofunctional (meth) acrylate compound having one hydroxyl group. The compound represented by the following formula (A) is more preferable. In the present invention, “(meth) acryl” is a term including one or both of “acryl” and “methacryl”, and also includes “(meth) acrylate”, “(meth)”. The same applies to “acryloyl”.

In formula (A), R ¹ represents an alkylene group, preferably an alkylene group having 2 to 20 carbon atoms, and more preferably an alkylene group having 2 to 10 carbon atoms.
Further, the alkylene group in R ¹ may be linear, branched or a ring structure. Moreover, the alkylene group in R ¹ may have a substituent. Preferred examples of the substituent include a halogen atom, a hydroxy group, an alkoxy group, an aryl group, and an aryloxy group.
In formula (A), R ² represents a hydrogen atom or a methyl group.
Specific examples of the (meth) acrylate compound having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxyoctyl (meta ) Acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate and 2-hydroxy-3-chloropropyl (meth) acrylate, diglycerol di (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, Cyclohexanoxy-β-hydroxypropyl (meth) acrylate, tetrahydrofurfuroxy-β-hydroxypropyl (meth) acrylate, nonyloxy-β-hydroxypropyl (meth) acrylate Etc. can be exemplified.
The (meth) acrylate compound having a hydroxyl group may be used alone or in combination of two or more.
The content of the (meth) acrylate compound having a hydroxyl group in the photocurable adhesive is preferably 10 to 80 parts by weight with respect to 100 parts by weight of the photocurable adhesive, and 20 to 65 parts by weight. It is more preferable.

[(Meth) acrylate compound having no hydroxyl group]
The said photocurable adhesive agent contains the (meth) acrylate compound which does not have a hydroxyl group other than the (meth) acrylate compound which has the said hydroxyl group.
The (meth) acrylate compound having no hydroxyl group is not particularly limited as long as it does not have a hydroxyl group, but it is preferable that the photocurable adhesive contains at least a polyfunctional (meth) acrylate compound having no hydroxyl group.
Preferred examples of the (meth) acrylate compound having no hydroxyl group include compounds represented by the following formulas (B-1) to (B-7).

In formula (B-1), R ³ represents a hydrogen atom or —CH ₃ , and R ⁴ each independently represents a hydrogen atom, —CH ₃ , —C ₂ H ₅ or a group represented by formula (B ′). R ⁵ represents each independently a hydrogen atom, a chlorine atom, —CH ₃ or —C ₂ H ₅ , and R ⁶ each independently represents a hydrogen atom or a group represented by the formula (B ′). , M each independently represents an integer of 1-8, n represents an integer of 1-20, and p independently represents 0 or 1.
Specific examples of the compound represented by the formula (B-1) include diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,2-propylene glycol di ( Examples include meth) acrylate, dipropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, and diglycerol tetra (meth) acrylate.

In formula (B-2), each R ⁷ independently represents a hydrogen atom or —CH ₃ , each R ⁸ independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, R Each ⁹ independently represents a linear or branched alkylene group having 2 to 4 carbon atoms, and each m independently represents an integer of 1 to 10.
Specific examples of the compound represented by the formula (B-2) include 2,2-bis (4-methacryloxydiethoxyphenyl) propane, 2,2-bis (4-methacryloxytriethoxyphenyl) propane, 2,2-bis (4-acryloxypentaethoxyphenyl) propane, 2,2-bis (4-methacryloxyhexaethoxyphenyl) propane, 2,2-bis (4-acryloxyheptaethoxyphenyl) propane, 2, 2-bis (4-methacryloxyoctaethoxyphenyl) propane, 2,2-bis (4-acryloxydipropoxyphenyl) propane, 2,2-bis (4-methacryloxytripropoxyphenyl) propane, 2,2- Bis (4-acryloxydiptooxyphenyl) propane, 2,2-bis (4-methacryloxyoctabutodi Cyphenyl) propane, 2- (4-methacryloxydiethoxyphenyl) -2- (4-methacryloxytriethoxyphenyl) propane, 2- (4-acryloxydipropoxyphenyl) -2- (4-acryloxytriethoxy) And phenyl) propane.

In formula (B-3), R ¹⁰ represents a hydrogen atom or —CH ₃ , R ¹¹ independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and n represents 0 to 10 Represents an integer.
Specific examples of the compound represented by the formula (B-3) include dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and dicyclopentenyloxypropyl (meth) acrylate.

In the formula (B-4), R ¹² represents a hydrogen atom or —CH ₃ , R ¹³ represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cyclic alkyl group having 5 to 20 carbon atoms, phenyl A group, a tetrahydrofurfuryl group, or a linear or branched alkyl group having 5 to 20 carbon atoms having these groups.
Specific examples of the compound represented by the formula (B-4) include methacrylic acid, acrylic acid, methyl (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, and 2-ethylhexyl (meth). Examples thereof include acrylate, phenyl (meth) acrylate, and benzyl (meth) acrylate.

In the formula (B-5), R ¹⁴ represents a hydrogen atom or —CH ₃ , and R ¹⁵ represents a linear or branched alkyl group having 1 to 20 carbon atoms, an alkenyl group, an aryl group, an aralkyl group, or a linear or branched alkoxy group. Represents an alkyl group.
Specific examples of the compound represented by the formula (B-5) include methoxycarbonylmethyl (meth) acrylate, ethoxycarbonylmethyl (meth) acrylate, heptoxycarbonylmethyl (meth) acrylate, and isopropoxycarbonylmethyl (meth). An acrylate etc. are mentioned.

In formula (B-6), each R ¹⁶ independently represents a hydrogen atom or —CH ₃ , each R ¹⁷ independently represents a linear or branched alkylene group having 2 to 4 carbon atoms, and m represents each Independently, it represents an integer of 1 to 10, and n represents 1 or 2.

In formula (B-7), each R ¹⁸ independently represents a hydrogen atom or —CH ₃ , each m independently represents an integer of 1 to 10, and n represents 1 or 2.
Specific examples of the compound represented by formula (B-6) or formula (B-7) include (meth) acryloxyethyl phosphate, 1-chloro-3- (meth) acryloxypropyl-2-phosphorus Examples thereof include acid and (meth) acryloxypropyl phosphoric acid.

Moreover, as the (meth) acrylate compound having no hydroxyl group, a (meth) acrylate compound having a urethane bond can be used.
Examples of the (meth) acrylate compound having a urethane bond include a reaction product of a (meth) acrylate compound having a hydroxyl group and an organic polyisocyanate compound, a (meth) acrylate compound having a hydroxyl group, an organic polyisocyanate compound, and a trivalent compound. The reaction product with the above polyol compound and / or diol compound is mentioned.
As a specific example, bis (glyceryl urethane) isophorone tetramethacrylate (the following compound) can be preferably exemplified.

Among these, the (meth) acrylate compound having no hydroxyl group preferably includes a compound represented by the formula (B-1) or a (meth) acrylate compound having a urethane bond. It is more preferable that the compound represented by this is included, and it is still more preferable that trimethylol propane tri (meth) acrylate is included.
The (meth) acrylate compound having no hydroxyl group may be used alone or in combination of two or more.
The content of the methacrylate compound having no hydroxyl group in the photocurable adhesive is preferably 20 to 90 parts by weight, and preferably 35 to 80 parts by weight with respect to 100 parts by weight of the photocurable adhesive. Is more preferable.

(Photopolymerization initiator)
The photocurable adhesive contains a photopolymerization initiator.
There is no restriction | limiting in particular as a photoinitiator, A well-known initiator can be used.
Examples of the photopolymerization initiator include (a) aromatic ketones, (b) onium salt compounds, (d) thio compounds, (e) hexaarylbiimidazole compounds, (f) ketoxime ester compounds, (g) borates. Compounds, (h) azinium compounds, (i) metallocene compounds, (j) active ester compounds, and (k) compounds having a carbon halogen bond. Examples of these radical polymerization initiators include those described in JP-A-2008-19408.
Specific examples of the photopolymerization initiator include, for example, Bruce M. Monroe et al., Chemical Reviews, 93, 435 (1993) and RS Davidson, Journal of Photochemistry and Biology A: Chemistry, 73, 81 (1993). JP Faussier "Photoinitiated Polymerization-Theory and Applications": Rapra Review, vol.9, Report, Rapra Technology (1998) and M. Tsunooka et al., Prog. Polym. Sci., 21, 1 (1996) Many are described. In addition, many compounds used as chemically amplified photoresists are described as photopolymerization initiators in Organic Electronics Materials Research Group, “Organic Materials for Imaging”, Bunshin Publishing (1993), pages 187-192. ing. Furthermore, FD Saeva, Topics in Current Chemistry, 156, 59 (1990), GG Maslak, Topics in Current Chemistry, 168, 1 (1993), HB Shuster et al, J. Am. Chem. Soc., 112, 6329 (1990), IDF Eaton et al, J. Am. Chem. Soc., 102, 3298 (1980), etc., through the interaction with the electronically excited state of the sensitizer, oxidative or A group of compounds that undergo reductive bond cleavage is also known as a photopolymerization initiator.

Specific examples of the photopolymerization initiator include benzyl, benzophenone, Michler's ketone, 2-chlorothioxysantone, 2,4-diethylthioxanthone, benzoin, benzoin ethyl ether, benzoin isobutyl ether, benzoin octyl ether, diethoxyacetophenone, Benzyl methyl ketal, 1-hydroxycyclohexyl phenyl ketone, diacetyl, methyl anthraquinone, acetophenone, 2-hydroxy-2-methylpropiophenone, anthraquinone, and 3,3 ′, 4,4′-tetra (tertiary butyl peroxy And carbonyl) benzophenone.
The photopolymerization initiators may be used alone or in combination of two or more.
The content of the photopolymerization initiator in the photocurable adhesive is preferably 0.1 to 20 parts by weight, and 0.1 to 10 parts by weight with respect to 100 parts by weight of the photocurable adhesive. It is more preferable.

[Other ingredients]
In addition to the above components, the photocurable adhesive may contain a known additive as required, but it is preferable not to include other components other than the above components.
Examples of the additive include a polymerization accelerator, a stabilizer, a colorant, and a viscosity modifier.
Examples of the polymerization accelerator include 1,2,3,4-tetrahydroquinoline, saccharin, triethylamine, N, N-dimethylaniline, and the like.
Examples of the stabilizer include oxalic acid, dinitrosolesorcinol, and quinones.
Examples of the viscosity modifier include polymer compounds such as resins, organic solvents, and the like.

<Adhesion process>
The method for producing a relief printing plate precursor for laser engraving of the present invention includes an adhesion step of curing the photocurable adhesive with light to adhere the recording layer and the support.
The light used in the bonding step is an actinic ray that can cure the photocurable adhesive by irradiation, and is not particularly limited as long as it is other than laser light that can engrave the relief printing plate precursor, Widely includes α rays, γ rays, X rays, ultraviolet rays (UV), visible rays, electron beams, and the like. Among these, it is particularly preferable to use ultraviolet rays as the light.
Laser light is light with high coherence and is excellent in directivity and convergence, and examples thereof include an infrared laser described later.
Although there is no restriction | limiting in particular as a light source which can be used for the said adhesion process, A mercury lamp, a metal halide lamp, etc. can illustrate preferably.
The exposure amount of light in the bonding step may be an amount which light curable adhesive is cured, but is preferably 10~4,000mJ / cm ^2, at 20~2,500mJ / cm ² More preferably.
In view of the ease of curing by light, at least one of the support and the recording layer is preferably transparent, and the support is more preferably a transparent support.
In the relief printing plate precursor, the peeling force between the recording layer and the support is preferably 2 N / cm or more, more preferably 3 N / cm or more, and more preferably 4 N / cm or more. Further preferred. Moreover, it is preferable that it is 20 N / cm or less.

Moreover, the manufacturing method of the relief printing plate precursor of the present invention may have a protective step of forming a peelable protective layer on the surface of the recording layer on the substrate side in the layer forming step of the recording layer, if necessary. Good. Examples of the method for providing the protective layer include a method in which the protective film and the recording layer are pressure-bonded with a heated calendar roll or the like, and a method in which the protective film is adhered to the recording layer impregnated with a small amount of solvent on the surface. It is done.
In the case of using a protective film, in the layer forming step, a method of first providing a protective film on a substrate and laminating a recording layer on the protective film may be employed.
In addition, when the protective film cannot be peeled off or is difficult to adhere to the recording layer, a slip coat layer may be provided between both layers. The material used for the slip coat layer is a resin that is soluble or dispersible in water, such as polyvinyl alcohol, polyvinyl acetate, partially saponified polyvinyl alcohol, hydroxyalkyl cellulose, alkyl cellulose, polyamide resin, etc. It is preferable that

Although there is no restriction | limiting in particular as a manufacturing apparatus used suitably for the manufacturing method of the relief printing plate precursor of this invention, For example, the apparatus shown in FIG. 1 is mentioned.
FIG. 1 is a schematic view showing an example of a production apparatus used in the method for producing a relief printing plate precursor according to the present invention.
The recording layer 12 formed on the substrate is wound around a recording layer roller 14 (not shown), and the recording layer 12 is conveyed from the recording layer roller 14 using the conveying means 16 or the like in the relief printing plate precursor manufacturing apparatus 10. . During the conveyance, the upper surface of the recording layer 12 is a surface (air surface) 12a facing the substrate-side surface in the layer forming step, and the lower surface of the recording layer 12 is the substrate-side surface 12b in the layer forming step. To do.
The transported recording layer 12 applies an adhesive to the air surface 12a by the adhesive applying means 18, and an adhesive layer 20 is formed.
Further, the support 24 conveyed from the support roller 22 is bonded to the recording layer 12 on which the adhesive layer 20 is formed by the nip rollers 26 and 28.
The recording layer 12 to which the support 24 is bonded is irradiated with ultraviolet rays from the support 24 side by the ultraviolet irradiation means 30, and the adhesive layer 20 is cured and bonded to obtain a relief printing plate precursor 32.

(Relief printing plate and plate making method)
The plate-making method of the relief printing plate of the present invention is an engraving step of forming a relief layer by laser engraving the recording layer of the relief printing plate precursor for laser engraving obtained by the method for producing a relief printing plate precursor for laser engraving of the present invention. ,including.
The relief printing plate of the present invention is a relief printing plate having a relief layer obtained by laser engraving a recording layer of a relief printing plate precursor for laser engraving obtained by the method for producing a relief printing plate precursor for laser engraving of the present invention. It is.
In the relief printing plate of the present invention, a water-based ink can be suitably used during printing.

<Engraving process>
The plate-making method of the relief printing plate of the present invention is an engraving step of forming a relief layer by laser engraving the recording layer of the relief printing plate precursor for laser engraving obtained by the method for producing a relief printing plate precursor for laser engraving of the present invention. including.
The engraving step is a step of forming a relief layer by laser engraving the recording layer. Specifically, it is preferable to form the relief layer by engraving the recording layer by irradiating a laser beam corresponding to a desired image. Further, a step of controlling the laser head with a computer based on digital data of a desired image and irradiating the recording layer with scanning is preferable.
In this engraving process, an infrared laser is preferably used. When irradiated with an infrared laser, the molecules in the recording layer undergo molecular vibration and heat is generated. When a high-power laser such as a carbon dioxide laser or YAG laser is used as an infrared laser, a large amount of heat is generated in the laser irradiation portion, and molecules in the recording layer are selectively cut by molecular cutting or ionization, that is, Sculpture is made. The advantage of laser engraving is that the engraving depth can be set arbitrarily, so that the structure can be controlled three-dimensionally. For example, a portion that prints fine halftone dots can be engraved shallowly or with a shoulder so that the relief does not fall down due to printing pressure, and a portion of a groove that prints fine punched characters is engraved deeply As a result, the ink is less likely to be buried in the groove, and it is possible to suppress the crushing of the extracted characters.
In particular, when engraving with an infrared laser corresponding to the absorption wavelength of the photothermal conversion agent, the recording layer can be selectively removed with higher sensitivity, and a relief layer having a sharp image can be obtained.

The infrared laser used in the engraving process is preferably a carbon dioxide laser (CO ₂ laser) or a semiconductor laser from the viewpoint of productivity, cost, etc., and a semiconductor infrared laser with a fiber (FC-LD) is particularly preferable. In general, a semiconductor laser can be downsized with high efficiency and low cost in laser oscillation compared to a CO ₂ laser. Moreover, since it is small, it is easy to form an array. Furthermore, the beam shape can be controlled by processing the fiber.
The semiconductor laser preferably has a wavelength of 700 to 1,300 nm, more preferably 800 to 1,200 nm, still more preferably 860 to 1,200 nm, and particularly preferably 900 to 1,100 nm.
Moreover, since the semiconductor laser with a fiber can output a laser beam efficiently by attaching an optical fiber, it is effective for the engraving process in the present invention. Furthermore, the beam shape can be controlled by processing the fiber. For example, the beam profile can have a top hat shape, and energy can be stably given to the plate surface. Details of semiconductor lasers are described in “Laser Handbook 2nd Edition” edited by Laser Society, Practical Laser Technology and Electronic Communication Society.
Also, a plate making apparatus equipped with a fiber-coupled semiconductor laser that can be suitably used in a method for making a relief printing plate using the relief printing plate precursor of the present invention is disclosed in JP 2009-172658 A and JP 2009-214334 A. And can be used for making a relief printing plate according to the present invention.

In the method for making a relief printing plate of the present invention, following the engraving step, the following rinsing step, drying step, and / or post-crosslinking step may be included as necessary.
Rinsing step: a step of rinsing the engraved surface of the relief layer surface after engraving with water or a liquid containing water as a main component.
Drying step: a step of drying the engraved relief layer.
Post-crosslinking step: a step of imparting energy to the relief layer after engraving and further crosslinking the relief layer.
Since the engraving residue adheres to the engraving surface after the above process, a rinsing step of rinsing the engraving residue by rinsing the engraving surface with water or a liquid containing water as a main component may be added. As a means of rinsing, there is a method of washing with tap water, a method of spraying high-pressure water, and a known batch type or conveying type brush type washing machine as a photosensitive resin relief printing machine. For example, when the engraving residue cannot be removed, a rinsing liquid to which soap or a surfactant is added may be used.
When the rinsing process for rinsing the engraved surface is performed, it is preferable to add a drying process for drying the engraved recording layer and volatilizing the rinsing liquid.
Furthermore, a post-crosslinking step for further cross-linking the recording layer may be added as necessary. By performing the post-crosslinking step, which is an additional cross-linking step, the relief formed by engraving can be further strengthened.

The pH of the rinsing solution that can be used in the present invention is preferably 9 or more, more preferably 10 or more, and still more preferably 11 or more. Moreover, it is preferable that the pH of a rinse liquid is 14 or less, It is more preferable that it is 13 or less, It is still more preferable that it is 12.5 or less. Handling is easy in the said range.
What is necessary is just to adjust pH using an acid and / or a base suitably in order to make a rinse liquid into said pH range, and the acid and base to be used are not specifically limited.
The rinsing liquid that can be used in the present invention preferably contains water as a main component.
Moreover, the rinse liquid may contain water miscible solvents, such as alcohol, acetone, tetrahydrofuran, etc. as solvents other than water.

It is preferable that the rinse liquid contains a surfactant.
As the surfactant that can be used in the present invention, a carboxybetaine compound, a sulfobetaine compound, a phosphobetaine compound, an amine oxide compound, or from the viewpoint of reducing engraving residue removal and influence on the relief printing plate, Preferred are betaine compounds (amphoteric surfactants) such as phosphine oxide compounds. In the present invention, N = O amine oxide compound, and, each structure of the P = O phosphine oxide ^{compounds, N + -O -, P +} -O - shall be regarded as.
Examples of the surfactant include known anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. Further, fluorine-based and silicone-based nonionic surfactants can be used in the same manner.
Surfactant may be used individually by 1 type, or may use 2 or more types together.
The amount of the surfactant used is not particularly limited, but is preferably 0.01 to 20% by weight, more preferably 0.05 to 10% by weight, based on the total weight of the rinse liquid. .

As described above, a relief printing plate having a relief layer is obtained.
The thickness of the relief layer of the relief printing plate is preferably 0.05 mm or more and 10 mm or less, more preferably 0.05 mm or more and 7 mm, from the viewpoint of satisfying various printability such as wear resistance and ink transferability. Hereinafter, it is particularly preferably 0.05 mm or more and 3 mm or less.

The Shore A hardness of the relief layer of the relief printing plate is preferably 50 ° or more and 90 ° or less. When the Shore A hardness of the relief layer is 50 ° or more, even if the fine halftone dots formed by engraving are subjected to the strong printing pressure of the relief printing press, they do not collapse and can be printed normally. In addition, when the Shore A hardness of the relief layer is 90 ° or less, it is possible to prevent faint printing in a solid portion even in flexographic printing with a kiss touch.
The Shore A hardness in the present specification is a durometer (spring type) in which an indenter (called a push needle or indenter) is pushed and deformed on the surface of the object to be measured, and the amount of deformation (pushing depth) is measured and digitized. It is a value measured by a rubber hardness meter.
The relief printing plate of the present invention is particularly suitable for printing with water-based ink by a flexographic printing machine, but printing is possible with any of water-based ink, oil-based ink and UV ink by a relief printing press. In addition, printing with UV ink by a flexographic printing machine is also possible.

<Resin engraving resin composition>
The recording layer in the method for producing a relief printing plate precursor for laser engraving of the present invention is preferably formed of a resin composition for laser engraving.
The resin composition for laser engraving (hereinafter also simply referred to as “resin composition”) that can be used in the present invention preferably contains a binder polymer, and preferably contains a binder polymer and a photothermal conversion agent. More preferably, the binder polymer, the photothermal conversion agent, and the crosslinking agent are further preferably contained, and the binder polymer, the photothermal conversion agent, and the reactive silane compound are particularly preferably contained.
As an application mode of the resin composition, specifically, an image forming layer of an image forming material for forming an image by laser engraving, a recording layer of a printing plate precursor for forming a convex relief by laser engraving, an intaglio, a stencil, Examples include, but are not limited to, stamps. Hereinafter, the components of the resin composition for laser engraving will be described.

[Crosslinking agent]
From the viewpoint of forming a crosslinked structure in the recording layer, the resin composition for laser engraving preferably contains a crosslinking agent in order to form the crosslinked structure.
The recording layer preferably has a crosslinked structure.
The crosslinking agent that can be used in the present invention is not particularly limited as long as it can be polymerized by a chemical reaction caused by light or heat to cure the recording layer. In particular, a polymerizable compound having an ethylenically unsaturated group (hereinafter also referred to as “polymerizable compound”), a reactive silane compound having a reactive silyl group such as an alkoxysilyl group or a halogenated silyl group, and a reactive titanium compound. A reactive aluminum compound is preferably used, and a reactive silane compound is more preferably used. These compounds may form a cross-linked structure in the recording layer by reacting with the binder, or may form a cross-linked structure by reacting with these compounds. A crosslinked structure may be formed.
The polymerizable compound that can be used here can be arbitrarily selected from compounds having at least 1, preferably 2 or more, more preferably 2 to 6 ethylenically unsaturated groups.

The resin composition for laser engraving preferably contains a compound having a group represented by the following formula (I) (hereinafter also referred to as “compound (I)”).
-M (R ¹ ) (R ² ) _n (I)
(In the formula (I), R ¹ represents OR ³ or a halogen atom, M represents Si, Ti, or Al. When M is Si, n is 2, and when M is Ti, n is 2. And when M is Al, n is 1, each of R ² independently represents a hydrocarbon group, OR ³ or a halogen atom, and R ³ represents a hydrogen atom or a hydrocarbon group.)

In formula (I), M represents Si, Ti, or Al. Among these, M is preferably Si or Ti, and more preferably Si.
In the formula (I), R ¹ represents OR ³ or a halogen atom, R ³ represents a hydrogen atom or a hydrocarbon group, and the hydrocarbon group includes an alkyl group having 1 to 30 carbon atoms and 6 to 30 carbon atoms. Aryl groups having 2 to 30 carbon atoms, aralkyl having 7 to 37 carbon atoms, and the like. Among these, R ³ is preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 20 carbon atoms, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or 6 to 6 carbon atoms. 10 aryl groups are more preferable, and a methyl group or ethyl group is particularly preferable. That is, R ¹ is particularly preferably a methoxy group or an ethoxy group.
R ¹ is -M (R ²⁾ _n O when treated with an alkaline rinse solution ^- is preferably one that ionized.

In the formula (I), R ² represents a hydrocarbon group, OR ³ or a halogen atom. R ³ is as described above, and the preferred range is also the same.
R ² is preferably OR ³ or a halogen atom, and more preferably OR ³ .

N is 2 when M is Si. When M is Si, a plurality of R ² may be the same or different, and is not particularly limited.
N is 2 when M is Ti. When M is Ti, a plurality of R ² may be the same or different, and is not particularly limited.
When M is Al, n represents 1.

  In addition, the compound (I) may be one in which a group represented by the above formula (I) is introduced into the polymer by reaction with a polymer, and has a group represented by the above formula (I) before the reaction, A group represented by the above formula (I) may be introduced into the polymer.

As the compound (I), an embodiment in which M is Si is particularly preferable.
The recording layer preferably has a siloxane bond.
When M is Si, a silane coupling agent can also be used as the compound having the group represented by the formula (I) (compound (I)). The silane coupling agent is a compound having a group capable of reacting with an inorganic component such as an alkoxysilyl group and a group capable of reacting with an organic component such as a methacryloyl group, and capable of binding the inorganic component and the organic component. is there. The same applies to titanium coupling agents and aluminate coupling agents.
Compound (I) has a reactive group such as a vinyl group, an epoxy group, a methacryloyloxy group, an acryloyloxy group, a mercapto group, and an amino group, and reacts with the polymer with the reactive group, whereby the polymer has the formula (I It is also preferred that a group represented by

Examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ -Glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ- Methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimeth Sisilane, N- (β-aminoethyl) -γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercapto Examples thereof include propyltrimethoxysilane, γ-chloropropyltrimethoxysilane, and γ-ureidopropyltriethoxysilane.
As the compound (I), a compound having a plurality of groups represented by the formula (I) is also preferably used. In such a case, the group represented by the formula (I) can be introduced into the polymer by reacting a part of the group represented by the formula (I) with the polymer. For example, the R ¹ group and optionally the R ² group of compound (I) react with an atom and / or group (eg, hydroxyl group (—OH)) that can react with the compound in the polymer (eg, alcohol exchange). react. In addition, when a plurality of groups represented by the formula (I) are bonded to the polymer, the compound (I) also functions as a crosslinking agent, and can form a crosslinked structure.
Such a compound (I) is preferably a compound having a plurality of groups represented by the formula (I), and preferably a compound having 2 to 6 groups represented by the formula (I). More preferred is a compound having 2 to 3 groups represented by the formula (I).
Although the compounds shown below are preferred, the present invention is not limited to these compounds.

In the above formulas, R represents a partial structure selected from the following structures. When a plurality of R and R ¹ are present in the molecule, these may be the same or different from each other, and are preferably the same in terms of synthesis suitability.

In the above formulas, R represents a partial structure shown below. R ¹ has the same meaning as described above. When a plurality of R and R ¹ are present in the molecule, these may be the same or different from each other, and are preferably the same in terms of synthesis suitability.

In the present invention, silica particles, titanium oxide particles, aluminum oxide particles, and the like can also be used as the compound (I). These particles can react with a polymer described later to introduce a group represented by the above formula (I) into the polymer. For example, -SiOH is introduced by the reaction between silica particles and a polymer described later.
Other examples of titanium coupling agents include Ajinomoto Fine Techno Co., Ltd. Preneact, Matsumoto Fine Chemical Co., Ltd. Titanium Tetraisopropoxide, Nippon Soda Co., Ltd. Titanium-i-propoxybis (acetylacetonato) titanium. An example of the aluminate coupling agent is acetoalkoxyaluminum diisopropylate.

In this invention, said compound (I) may be used individually by 1 type, and may use 2 or more types together.
In the present invention, the content of the compound (I) contained in the resin composition for laser engraving is preferably 0.1 to 80% by weight, more preferably 1 to 40% by weight in terms of solid content. 5 to 30% by weight is more preferable.

In the present invention, from the viewpoint of forming a crosslinked structure in the recording layer, the resin composition for laser engraving preferably contains a polymerizable compound in order to form the crosslinked structure.
The polymerizable compound that can be used here can be arbitrarily selected from compounds having at least one ethylenically unsaturated group, preferably two or more, and more preferably 2 to 6.
Further, in the present invention, in addition to the purpose of forming a crosslinked structure, from the viewpoint of film properties such as flexibility and brittleness, etc., compounds having only one ethylenically unsaturated group (monofunctional polymerizable compound, monofunctional monomer) ) May be used.

Hereinafter, a compound (monofunctional monomer) having one ethylenically unsaturated group in the molecule and a compound (polyfunctional monomer) having two or more ethylenically unsaturated groups in the molecule used as a polymerizable compound explain.
Since the recording layer needs to have a crosslinked structure in the film, a polyfunctional monomer is preferably used. The molecular weight of these polyfunctional monomers is preferably 200 to 2,000.
Examples of monofunctional monomers and polyfunctional monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) and esters of polyhydric alcohol compounds, unsaturated carboxylic acids, Examples include amides with polyvalent amine compounds.

In the present invention, from the viewpoint of improving engraving sensitivity, a compound having a sulfur atom in the molecule is preferably used as the polymerizable compound.
Thus, as a polymeric compound which has a sulfur atom in a molecule | numerator, from a viewpoint of an engraving sensitivity improvement, it has two or more ethylenically unsaturated bonds especially, and connects between two ethylenically unsaturated bonds among them. It is preferable to use a polymerizable compound having a carbon-sulfur bond at the site (hereinafter also referred to as “sulfur-containing polyfunctional monomer” as appropriate).

The functional group containing a carbon-sulfur bond in the sulfur-containing polyfunctional monomer in the present invention includes sulfide, disulfide, sulfoxide, sulfonyl, sulfonamide, thiocarbonyl, thiocarboxylic acid, dithiocarboxylic acid, sulfamic acid, thioamide, and thiocarbamate. , Functional groups containing dithiocarbamate or thiourea.
In addition, as a linking group containing a carbon-sulfur bond that connects two ethylenically unsaturated bonds in a sulfur-containing polyfunctional monomer, -C-S-, -CSS-, -NH (C = It is preferably at least one unit selected from the group consisting of S) O—, —NH (C═O) S—, —NH (C═S) S—, and —C—SO ₂ —.

Further, the number of sulfur atoms contained in the molecule of the sulfur-containing polyfunctional monomer is not particularly limited as long as it is 1 or more, and can be appropriately selected according to the purpose, but the engraving sensitivity and the solubility in a coating solvent. From the viewpoint of balance, 1 to 10 is preferable, 1 to 5 is more preferable, and 1 to 2 is still more preferable.
On the other hand, the number of ethylenically unsaturated groups contained in the molecule is not particularly limited as long as it is 2 or more, and can be appropriately selected according to the purpose. -10 are preferable, 2-6 are more preferable, and 2-4 are still more preferable.

The molecular weight of the sulfur-containing polyfunctional monomer in the present invention is preferably 120 to 3,000, more preferably 120 to 1,500, from the viewpoint of the flexibility of the formed film.
Moreover, although the sulfur-containing polyfunctional monomer in this invention may be used independently, you may use it as a mixture with the polyfunctional polymerizable compound and monofunctional polymerizable compound which do not have a sulfur atom in a molecule | numerator.
From the viewpoint of engraving sensitivity, it is preferable to use the sulfur-containing polyfunctional monomer alone or as a mixture of the sulfur-containing polyfunctional monomer and the monofunctional monomer, and use it as a mixture of the sulfur-containing polyfunctional monomer and the monofunctional monomer. Embodiments are more preferred.

In the recording layer, film properties such as brittleness and flexibility can be adjusted by using a polymerizable compound such as a sulfur-containing polyfunctional monomer.
In addition, the total content of the polymerizable compound including the sulfur-containing polyfunctional monomer in the resin composition is preferably 10 to 60% by weight with respect to the nonvolatile component from the viewpoint of the flexibility and brittleness of the crosslinked film. The range of 15 to 45% by weight is more preferable.
In addition, when using together a sulfur-containing polyfunctional monomer and another polymeric compound, 5 weight% or more is preferable and, as for the quantity of the sulfur-containing polyfunctional monomer in all the polymeric compounds, 10 weight% or more is more preferable.

[Binder polymer]
The resin composition for laser engraving preferably contains a binder polymer (hereinafter also referred to as “binder”).
The binder is a polymer component contained in the resin composition for laser engraving, and a general polymer compound can be appropriately selected and used alone or in combination of two or more. In particular, when a resin composition for laser engraving is used for a printing plate precursor, it is necessary to select it in consideration of various performances such as laser engraving property, ink acceptability, and engraving residue dispersibility.
The binder includes polystyrene resin, polyester resin, polyamide resin, polyurea resin, polyamideimide resin, polyurethane resin, polysulfone resin, polyethersulfone resin, polyimide resin, polycarbonate resin, hydrophilic polymer containing hydroxyethylene units, acrylic resin, acetal. A resin, an epoxy resin, a polycarbonate resin, rubber, a thermoplastic elastomer, or the like can be selected and used.

  For example, from the viewpoint of laser engraving sensitivity, a polymer containing a partial structure that is thermally decomposed by exposure or heating is preferable. Preferred examples of such a polymer include those described in paragraph 0038 of JP2008-163081A. For example, when the purpose is to form a soft and flexible film, a soft resin or a thermoplastic elastomer is selected. This is described in detail in paragraphs 0039 to 0040 of JP 2008-163081 A. Furthermore, if the resin composition for laser engraving is applied to the recording layer in the relief printing plate precursor for laser engraving, the ease of preparation of the resin composition for laser engraving and the oil-based ink in the resulting relief printing plate From the viewpoint of improving resistance, it is preferable to use a hydrophilic or alcoholic polymer. As the hydrophilic polymer, those described in detail in paragraph 0041 of JP-A-2008-163081 can be used.

In addition, when used for the purpose of curing by heating or exposure and improving the strength, a polymer having a carbon-carbon unsaturated bond in the molecule is preferably used.
As such a binder, examples of the polymer containing a carbon-carbon unsaturated bond in the main chain include SB (polystyrene-polybutadiene), SBS (polystyrene-polybutadiene-polystyrene), SIS (polystyrene-polyisoprene-polystyrene), SEBS. (Polystyrene-polyethylene / polybutylene-polystyrene) and the like.
As a polymer having a carbon-carbon unsaturated bond in the side chain, a carbon-carbon unsaturated bond such as an allyl group, an acryloyl group, a methacryloyl group, a styryl group, or a vinyl ether group is introduced into the side chain of the polymer. Can be obtained. The method for introducing a carbon-carbon unsaturated bond into the polymer side chain is as follows. (1) A structural unit having a polymerizable group precursor formed by bonding a protective group to a polymerizable group is copolymerized with the polymer to remove the protective group. (2) A polymer compound having a plurality of reactive groups such as a hydroxyl group, an amino group, an epoxy group, and a carboxyl group, and a group that reacts with these reactive groups and carbon- A known method such as a method of introducing a compound having a carbon unsaturated bond by polymer reaction can be employed. According to these methods, the amount of unsaturated bond and polymerizable group introduced into the polymer compound can be controlled.

As the binder, it is particularly preferable to use a polymer having a hydroxyl group (—OH) (hereinafter also referred to as “specific polymer”). The skeleton of the specific polymer is not particularly limited, but an acrylic resin, an epoxy resin, a hydrophilic polymer containing a hydroxyethylene unit, a polyvinyl acetal resin, a polyester resin, and a polyurethane resin are preferable.
As an acrylic monomer used for the synthesis of an acrylic resin having a hydroxyl group, for example, (meth) acrylic acid esters and crotonic acid esters (meth) acrylamides having a hydroxyl group in the molecule are preferable. Specific examples of such a monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like. A copolymer obtained by polymerizing these and a known (meth) acrylic monomer or vinyl monomer can be preferably used.
It is also possible to use an epoxy resin having a hydroxy group in the side chain as the specific polymer. As a preferred specific example, an epoxy resin obtained by polymerizing an adduct of bisphenol A and epichlorohydrin as a raw material monomer is preferable.
As the polyester resin, a polyester resin composed of hydroxyl carboxylic acid units such as polylactic acid can be preferably used. Specific examples of the polyester resin include polyhydroxyalkanoate (PHA), lactic acid-based polymer, polyglycolic acid (PGA), polycaprolactone (PCL), poly (butylene succinic acid), and derivatives or mixtures thereof. Those selected from the group consisting of are preferred.

The specific polymer is preferably a polymer having an atom and / or group capable of reacting with the compound (I), and is a polymer having an atom and / or group capable of reacting with the compound (I) and is insoluble in water. And it is more preferable that it is a binder polymer soluble in a C1-C4 alcohol.
Although it does not specifically limit as an atom and / or group which can react with the said compound (I), An ethylenically unsaturated bond, an epoxy group, an amino group, a (meth) acryloyl group, a mercapto group, a hydroxy group is illustrated, These Of these, a hydroxy group is preferred.
As a specific polymer in the present invention, polyvinyl butyral (PVB), an acrylic resin having a hydroxyl group in a side chain, and a film having good engraving sensitivity and good film property while achieving both water-based ink suitability and UV ink suitability Preferred examples include an epoxy resin having a hydroxyl group in the side chain.

  The specific polymer that can be used in the present invention is a photothermal conversion agent capable of absorbing light having a wavelength of 700 to 1,300 nm, which will be described later, which is a preferred combined component of the resin composition for laser engraving constituting the recording layer in the present invention. When combined with the above, it is particularly preferable that the glass transition temperature (Tg) is 20 ° C. or higher because engraving sensitivity is improved. Hereinafter, a polymer having such a glass transition temperature is referred to as a non-elastomer. That is, an elastomer is generally defined academically as a polymer having a glass transition temperature of room temperature or lower (see Science Dictionary 2nd edition, Editor International Science Promotion Foundation, published by Maruzen Co., Ltd., P154). . Therefore, a non-elastomer refers to a polymer having a glass transition temperature exceeding normal temperature. Although there is no restriction | limiting in the upper limit of the glass transition temperature of a specific polymer, it is preferable from a viewpoint of handleability that it is 200 degrees C or less, and it is more preferable that it is 25 degreeC or more and 120 degrees C or less.

When a polymer having a glass transition temperature of room temperature (20 ° C) or higher is used, the specific polymer takes a glass state at room temperature. It is in. In laser engraving, in addition to the heat imparted by the infrared laser during laser irradiation, the heat generated by the function of the photothermal conversion agent used in combination with the desired heat is transferred to a specific polymer around it, which decomposes and dissipates. As a result, engraving is performed to form a recess.
When a specific polymer is used, if a photothermal conversion agent is present in a state where thermal molecular motion of the specific polymer is suppressed, heat transfer to the specific polymer and thermal decomposition are considered to occur effectively. It is presumed that the engraving sensitivity is further increased by the effect.

  Specific examples of the binder preferably used in the present invention are illustrated below.

(1) Polyvinyl acetal and derivatives thereof Polyvinyl acetal is a compound obtained by cyclic acetalization of polyvinyl alcohol (obtained by saponifying polyvinyl acetate). Further, the polyvinyl acetal derivative is obtained by modifying the polyvinyl acetal or adding another copolymer component.
30 to 90% is preferable, and 50 to 85% is more preferable, and the acetal content in the polyvinyl acetal (the total number of moles of the vinyl acetate monomer as a raw material is 100%, and the mol% of vinyl alcohol units to be acetalized) is 55. -78% is particularly preferred.
The vinyl alcohol unit in the polyvinyl acetal is preferably 10 to 70 mol%, more preferably 15 to 50 mol%, and particularly preferably 22 to 45 mol%, based on the total number of moles of the starting vinyl acetate monomer.
Moreover, the polyvinyl acetal may have a vinyl acetate unit as another component, and as its content, 0.01-20 mol% is preferable and 0.1-10 mol% is still more preferable. The polyvinyl acetal derivative may further have other copolymer units.
Examples of the polyvinyl acetal include polyvinyl butyral, polyvinyl propylal, polyvinyl ethylal, and polyvinyl methylal. Among these, polyvinyl butyral (PVB) is preferable.
Polyvinyl butyral is usually a polymer obtained by converting polyvinyl alcohol into butyral. A polyvinyl butyral derivative may also be used.
Examples of polyvinyl butyral derivatives include acid-modified PVB in which at least part of the hydroxyl group is modified to an acid group such as a carboxyl group, modified PVB in which part of the hydroxyl group is modified to a (meth) acryloyl group, and at least part of the hydroxyl group is an amino group Modified PVB, modified PVB in which ethylene glycol, propylene glycol, or a multimer thereof is introduced into at least a part of the hydroxyl group.
The molecular weight of the polyvinyl acetal is preferably 5,000 to 800,000, more preferably 8,000 to 500,000 as a weight average molecular weight from the viewpoint of maintaining a balance between engraving sensitivity and film property. Furthermore, from the viewpoint of improving the rinse performance of engraving residue, it is particularly preferably 50,000 to 300,000.

Hereinafter, although polyvinyl butyral (PVB) and its derivative (s) are mentioned and demonstrated as a particularly preferable example of polyvinyl acetal, it is not limited to this.
As PVB, it can also be obtained as a commercial product, and preferred specific examples thereof include “ESREC B” series and “ESREC K” manufactured by Sekisui Chemical Co., Ltd. from the viewpoint of alcohol solubility (particularly ethanol solubility). (KS) "series," Denkabutyral "manufactured by Denki Kagaku Kogyo Co., Ltd. are preferred. More preferably, from the viewpoint of alcohol solubility (especially ethanol), “S-Lec B” series manufactured by Sekisui Chemical Co., Ltd. and “Denka Butyral” manufactured by Denki Kagaku Kogyo Co., Ltd. are particularly preferable. In the “ES REC B” series manufactured by Co., Ltd., “BL-1”, “BL-1H”, “BL-2”, “BL-5”, “BL-S”, “BX-L”, “BM-” "# 3000-1", "# 3000-2", "# 3000-4", "# 4000-2", "S", "BH-S", and Denka Butyral manufactured by Denki Kagaku Kogyo Co., Ltd. “# 6000-C”, “# 6000-EP”, “# 6000-CS”, “# 6000-AS”.
When a recording layer is formed using PVB as a specific polymer, a method in which a solution dissolved in a solvent is cast and dried is preferable from the viewpoint of the smoothness of the film surface.

  In addition to the polyvinyl acetal and derivatives thereof, the specific polymer may be an acrylic resin obtained using a known acrylic monomer and having a hydroxyl group in the molecule. In addition, a novolak resin that is a resin obtained by condensing phenols and aldehydes under acidic conditions can also be used as the specific polymer. Moreover, it is also possible to use the epoxy resin which has a hydroxyl group in a side chain as a specific polymer.

Among the specific polymers, polyvinyl butyral and derivatives thereof are particularly preferable from the viewpoint of rinsing properties and printing durability when used as a recording layer.
The content of the hydroxyl group contained in the specific polymer in the present invention is preferably 0.1 to 15 mmol / g, more preferably 0.5 to 7 mmol / g in any of the above-described polymers. .
Only 1 type of binder may be used for a resin composition, and 2 or more types may be used together.
The weight average molecular weight (polystyrene conversion by GPC measurement) of the binder that can be used in the present invention is preferably 5,000 to 1,000,000, more preferably 8,000 to 750,000. Most preferably, it is from 1,000,000 to 500,000.
The preferred content of the specific polymer in the resin composition that can be used in the present invention is 2 to 95% by weight in the total solid content, from the viewpoint of satisfying a good balance of form retention, water resistance and engraving sensitivity of the coating film. It is preferable that it is preferably 5 to 80% by weight, particularly preferably 10 to 60% by weight.
The content of the binder polymer is preferably 5 to 95% by weight, more preferably 15 to 80% by weight, and still more preferably 20 to 65% by weight based on the total solid content of the resin composition for laser engraving.
For example, when the resin composition for laser engraving is applied to the recording layer of the relief printing plate precursor, it is sufficient to use the obtained relief printing plate as a printing plate by setting the binder polymer content to 5% by weight or more. Printing durability is obtained, and by making it 95% by weight or less, other components are not deficient, and flexibility sufficient for use as a printing plate is obtained even when a relief printing plate is used as a flexographic printing plate. be able to.

〔solvent〕
In the present invention, the solvent used for preparing the resin composition is preferably mainly an aprotic organic solvent from the viewpoint of promptly proceeding the reaction between the compound (I) and the specific polymer. More specifically, it is preferable to use aprotic organic solvent / protic organic solvent = 100/0 to 50/50 (weight ratio). More preferably, it is 100 / 0-70 / 30, Most preferably, it is 100 / 0-90 / 10.
Preferred specific examples of the aprotic organic solvent include acetonitrile, tetrahydrofuran, dioxane, toluene, propylene glycol monomethyl ether acetate, methyl ethyl ketone, acetone, methyl isobutyl ketone, ethyl acetate, butyl acetate, ethyl lactate, N, N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide.
Preferred specific examples of the protic organic solvent are methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 1-methoxy-2-propanol, ethylene glycol, diethylene glycol, and 1,3-propanediol.

[Alcohol exchange reaction catalyst]
When using the compound (I) in the resin composition, it is preferable to contain an alcohol exchange reaction catalyst in order to promote the reaction between the compound (I) and the specific binder polymer.
The alcohol exchange reaction catalyst can be applied without limitation as long as it is a commonly used reaction catalyst.
Hereinafter, an acid or basic catalyst, which is a typical alcohol exchange reaction catalyst, and a metal complex catalyst will be sequentially described.

-Acidic catalyst or basic catalyst-
As the catalyst, an acidic catalyst or a basic catalyst is used as it is, or a catalyst dissolved in water or an organic solvent is used. The concentration at the time of dissolving in the solvent is not particularly limited, and may be appropriately selected according to the characteristics of the acid or basic compound used, the desired content of the catalyst, and the like.
The type of acidic catalyst or basic catalyst is not particularly limited. Specifically, examples of the acidic catalyst include hydrogen halides such as hydrochloric acid, nitric acid, sulfuric acid, sulfurous acid, hydrogen sulfide, perchloric acid, hydrogen peroxide, carbonic acid, Examples of the basic catalyst include carboxylic acids such as formic acid and acetic acid, substituted carboxylic acids obtained by substituting R of the structural formula represented by RCOOH with other elements or substituents, sulfonic acids such as benzenesulfonic acid, and phosphoric acid. Include ammoniacal bases such as aqueous ammonia and amines such as ethylamine and aniline. From the viewpoint of promptly proceeding the alcohol exchange reaction in the layer, methanesulfonic acid, p-toluenesulfonic acid, pyridinium p-toluenesulfonate, phosphoric acid, phosphonic acid, and acetic acid are preferable, and methanesulfonic acid, p-toluenesulfonic acid. Phosphoric acid is particularly preferred.

-Metal complex catalyst-
In the present invention, the metal complex catalyst used as the alcohol exchange reaction catalyst is preferably a metal element selected from the group consisting of groups 2, 4, 5 and 13 of the periodic table and a β-diketone (acetylacetone is preferred). , A ketoester, a hydroxycarboxylic acid or ester thereof, an amino alcohol, and an oxo or hydroxy oxygen compound selected from the group consisting of enolic active hydrogen compounds.
Further, among the constituent metal elements, group 2 elements such as Mg, Ca, St and Ba, group 4 elements such as Ti and Zr, group 5 elements such as V, Nb and Ta, and 13 such as Al and Ga. Group elements are preferred, and each form a complex having an excellent catalytic effect. Among them, a metal complex catalyst of Zr, Al, or Ti is preferable, and ethyl orthotitanate is particularly preferable because the obtained complex is excellent.
These are excellent in stability in aqueous coating solutions and in gelation promoting effect in sol-gel reaction during heat drying. Among them, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate), di ( Particularly preferred are acetylacetonato) titanium complex and zirconium tris (ethylacetoacetate).
In the resin composition, only one type of alcohol exchange reaction catalyst may be used, or two or more types may be used in combination. The content of the alcohol exchange reaction catalyst in the resin composition is preferably 0.01 to 20% by weight and more preferably 0.1 to 10% by weight with respect to the polymer having a hydroxyl group.

(Polymerization initiator)
The resin composition for laser engraving preferably contains a polymerization initiator, and more preferably uses a compound having an ethylenically unsaturated group and a polymerization initiator in combination.
A well-known thing can be used for a polymerization initiator without a restriction | limiting. Hereinafter, although the radical polymerization initiator which is a preferable polymerization initiator is explained in full detail, this invention is not restrict | limited by these description.
The polymerization initiator can be roughly classified into a photopolymerization initiator and a thermal polymerization initiator.
As the photopolymerization initiator, those described above can be suitably used.

  In the present invention, a thermal polymerization initiator is preferably used from the viewpoint of improving the degree of crosslinking. As the thermal polymerization initiator, (c) an organic peroxide and (l) an azo compound are preferably used, and (c) an organic peroxide is more preferably used. In particular, the following compounds are preferred.

(C) Organic peroxide As a radical polymerization initiator that can be used in the present invention, preferred (c) organic peroxide is 3,3′4,4′-tetra (t-butylperoxycarbonyl) benzophenone. 3,3′4,4′-tetra (t-amylperoxycarbonyl) benzophenone, 3,3′4,4′-tetra (t-hexylperoxycarbonyl) benzophenone, 3,3′4,4′- Tetra (t-octylperoxycarbonyl) benzophenone, 3,3′4,4′-tetra (cumylperoxycarbonyl) benzophenone, 3,3′4,4′-tetra (p-isopropylcumylperoxycarbonyl) benzophenone, Peroxide esters such as di-t-butyldiperoxyisophthalate are preferred.

(L) Azo compound As a radical polymerization initiator that can be used in the present invention, preferred (l) azo compounds include 2,2′-azobisisobutyronitrile and 2,2′-azobispropio. Nitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2, 2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 4,4′-azobis (4-cyanovaleric acid), dimethyl 2,2′-azobisisobutyrate, 2,2′-azobis (2- Methylpropionamidooxime), 2,2′-azobis [2- (2-imidazolin-2-yl) propane], 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl)] − -Hydroxyethyl] propionamide}, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2′-azobis (N-butyl-2-methylpropionamide), 2 , 2′-azobis (N-cyclohexyl-2-methylpropionamide), 2,2′-azobis [N- (2-propenyl) -2-methylpropionamide], 2,2′-azobis (2,4,4) 4-trimethylpentane) and the like.

The polymerization initiator in the present invention may be used alone or in combination of two or more.
The polymerization initiator can be added at a ratio of preferably 0.01 to 10% by weight, more preferably 0.1 to 3% by weight, based on the total solid content of the resin composition for laser engraving.

[Photothermal conversion agent]
The recording layer preferably contains a photothermal conversion agent.
The resin composition for laser engraving preferably contains a photothermal conversion agent.
It is considered that the photothermal conversion agent promotes thermal decomposition of the cured product of the resin composition for laser engraving by absorbing laser light and generating heat. Therefore, it is preferable to select a photothermal conversion agent that absorbs light having a laser wavelength used for engraving.

When a laser (YAG laser, semiconductor laser, fiber laser, surface emitting laser, etc.) emitting an infrared ray having a wavelength of 700 nm to 1,300 nm is used as a light source for laser engraving, the recording layer in the present invention has a recording layer of 700 nm to 1,300 nm. It is preferable to contain a photothermal conversion agent that can absorb light of a wavelength.
Various dyes and / or pigments are used as the photothermal conversion agent in the present invention.
More preferably, the photothermal conversion agent is at least one photothermal conversion agent selected from pigments and dyes having absorption at 800 nm to 1,200 nm.
The photothermal conversion agent is preferably a pigment.

  Among the photothermal conversion agents, as the dye, commercially available dyes and known ones described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specific examples include those having a maximum absorption wavelength at 700 nm to 1,300 nm. Azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, diimmonium compounds, quinone imine dyes , Methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, and metal thiolate complexes. In particular, cyanine dyes such as heptamethine cyanine dye, oxonol dyes such as pentamethine oxonol dye, and phthalocyanine dyes are preferably used. Examples thereof include the dyes described in paragraphs 0124 to 0137 of JP-A-2008-63554.

  Among the photothermal conversion agents used in the present invention, commercially available pigments and color index (CI) manuals, “latest pigment manuals” (edited by the Japan Pigment Technical Association, published in 1977), “latest pigment application” The pigments described in “Technology” (CMC Publishing, 1986) and “Printing Ink Technology” CMC Publishing, 1984) can be used.

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Of these pigments, carbon black is preferred.

As long as the dispersibility in the composition is stable, carbon black can be used regardless of the classification according to ASTM or the use (for example, for color, for rubber, for dry battery, etc.). Carbon black includes, for example, furnace black, thermal black, channel black, lamp black, acetylene black and the like. In addition, black colorants such as carbon black can be used as color chips or color pastes previously dispersed in nitrocellulose or the like by using a dispersant as required in order to facilitate dispersion. Chips and pastes are easily available as commercial products.
In the present invention, it is also possible to use carbon black having a relatively low specific surface area and relatively low DBP absorption and even finer carbon black having a large specific surface area. Examples of suitable carbon blacks include Printex® U, Printex® A, or Specialschwarz® 4 (from Degussa).
The carbon black that can be used in the present invention preferably has a dibutyl phthalate (DBP) oil absorption of less than 150 ml / 100 g.
Further, as the carbon black, conductive carbon black having a specific surface area of at least 150 m ² / g is preferable from the viewpoint of improving engraving sensitivity by efficiently transferring heat generated by photothermal conversion to surrounding polymers. .

  The content of the photothermal conversion agent in the recording layer or the resin composition for laser engraving varies greatly depending on the molecular extinction coefficient specific to the molecule, but the total solid weight of the resin composition or the recording layer. A range of 0.01 to 20% by weight is preferable, a range of 0.05 to 10% by weight is more preferable, and a range of 0.1 to 5% by weight is particularly preferable.

<Other additives>
The resin composition for laser engraving and the recording layer of the relief printing plate precursor may contain known additives in addition to those described above.
The resin composition for laser engraving preferably contains a plasticizer.
The plasticizer has a function of softening a film formed of the resin composition for laser engraving and needs to be compatible with the polymer.
As the plasticizer, for example, dioctyl phthalate, didodecyl phthalate, tributyl citrate, polyethylene glycols, polypropylene glycol (monool type or diol type), polypropylene glycol (monool type or diol type), etc. are preferably used. .
The resin composition for laser engraving is more preferably added with nitrocellulose or a highly thermally conductive substance as an additive for improving engraving sensitivity. Since nitrocellulose is a self-reactive compound, it generates heat during laser engraving and assists in the thermal decomposition of coexisting polymers such as hydrophilic polymers. As a result, it is estimated that the engraving sensitivity is improved. The highly heat conductive material is added for the purpose of assisting heat transfer, and examples of the heat conductive material include inorganic compounds such as metal particles and organic compounds such as a conductive polymer. As the metal particles, gold fine particles, silver fine particles, and copper fine particles having a particle size of micrometer order to several nanometer order are preferable. As the conductive polymer, a conjugated polymer is particularly preferable, and specific examples include polyaniline and polythiophene.
Moreover, the sensitivity at the time of photocuring the resin composition for laser engraving can be further improved by using a co-sensitizer.
Furthermore, it is preferable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization of the polymerizable compound during the production or storage of the composition.
Colorants such as dyes or pigments may be added for the purpose of coloring the resin composition for laser engraving. Thereby, properties such as the visibility of the image portion and the suitability of the image density measuring device can be improved.
Furthermore, in order to improve the physical properties of the cured film of the resin composition for laser engraving, a known additive such as a filler may be added.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

<Each component used for photocurable adhesive>
・ 2-hydroxypropyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.)
・ 2-Hydroxy-3-phenoxypropyl acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.)
・ Methyl methacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.)
・ Trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.)
・ Bis (glyceryl urethane) isophorone tetramethacrylate ・ 1-hydroxycyclohexyl phenyl ketone (Ciba Specialty Chemicals)
・ 2,4-Diethylthioxanthone (Ciba Specialty Chemicals)
・ Ethanol (Wako Pure Chemical Industries, Ltd.)

<Preparation of photocurable adhesive>
Each component shown in Table 1 was mixed with the following usage-amount, and each photocurable adhesive was produced.
-(Meth) acrylate compound having a hydroxyl group 52 parts by weight-(Meth) acrylate compound having no hydroxyl group 40 parts by weight-Photopolymerization initiator Amount shown in Table 1

  In Example 13, the amount of the (meth) acrylate compound having a hydroxyl group is 30 parts by weight, and the amount of the (meth) acrylate compound having no hydroxyl group is 62% by weight. In Example 14, the hydroxyl group has a hydroxyl group ( The amount of the (meth) acrylate compound used was 70 parts by weight, and the amount of the (meth) acrylate compound having no hydroxyl group was 22% by weight. Moreover, the photocurable adhesive used in Example 15 was adjusted to a solid content of 95% by adding ethanol.

<Preparation of Resin Composition 1 for Laser Engraving>
In a three-necked flask equipped with a stirring blade and a condenser tube, Gosenal T-215 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., water-soluble PVA) as a specific polymer, 50 parts by weight, and propylene glycol monomethyl ether acetate as a solvent, 47 parts by weight And heated at 70 ° C. for 120 minutes with stirring to dissolve the polymer. Thereafter, the solution was brought to 40 ° C., 15 parts by weight of tributyl citrate as a plasticizer, 8 parts by weight of Bremer LMA (manufactured by NOF Corporation) as a polymerizable compound (monofunctional), and perbutyl Z (as a polymerization initiator) 1.6 parts by weight of NOF Co., Ltd.) and 1 part by weight of carbon black (Show Black N110, Cabot Japan Co., Ltd., DBP oil absorption 115 ml / 100 g) as a photothermal conversion agent were added for 30 minutes. Stir. Then, compound (I) (SC-1) [The structure is shown below. Available under the trade name KBE-846 from Shin-Etsu Chemical Co., Ltd. 15 parts by weight and 0.4 part by weight of phosphoric acid as a catalyst were added and stirred at 40 ° C. for 10 minutes. By this operation, a fluid coating solution for a relief forming layer (laser engraving resin composition) was obtained.

なお、Ｅｔはエチル基を表す。

Et represents an ethyl group.

<Preparation of resin composition 2 for laser engraving>
A relief is obtained in the same manner as in the production of the resin composition 1 for laser engraving except that GOHSENAL T-215 is replaced with Denkabutyral # 3000-2 (manufactured by Denki Kagaku Kogyo Co., Ltd., polyvinyl butyral, Mw = 90,000). A coating liquid for forming layer was prepared.

<Preparation of resin composition 3 for laser engraving>
A relief forming layer coating solution was prepared in the same manner as in the preparation of the resin composition 2 for laser engraving except that SC-1 and phosphoric acid were not used.

<Preparation of Resin Composition 4 for Laser Engraving>
In a three-necked flask equipped with a stirring blade and a cooling tube, 50 parts by weight of ELASTOSIL (registered trademark: Type R300 / 30S, Wacker silicone rubber) and 47 parts by weight of tetrahydrofuran as a solvent are stirred and dissolved to dissolve the polymer. I let you. Thereafter, 0.8 part by weight of carbon black (Show Black N110, manufactured by Cabot Japan Co., Ltd., DBP oil absorption 115 ml / 100 g) was added as a photothermal conversion agent and stirred for 30 minutes. By this operation, a fluid coating solution for a relief forming layer (laser engraving resin composition) was obtained.
A resin composition 4 for laser engraving was produced in the same manner as the production of the resin composition 1 for laser engraving, except that the coating liquid for relief forming layer was used.

<Preparation of Resin Composition 5 for Laser Engraving>
Toughprene A (Asahi Kasei Co., Ltd., styrene-butadiene block copolymer) 60 parts by weight, B-2000 (Nippon Petrochemical Co., Ltd., liquid polybutadiene) 30 parts by weight, 1,9-nonanediol diacrylate 7 parts by weight, 2 parts by weight of 2,2-dimethoxy-2-phenylacetophenone and 1 part by weight of 2,6-di-t-butyl-p-cresol were kneaded with a kneader to prepare a resin composition 5 for laser engraving. .

<Method for producing relief printing plate precursor>
According to the prescription described in Table 1, each relief printing plate precursor was prepared by the following operation.
A spacer (frame) with a predetermined thickness is placed on the PET substrate, and the coating solution for the relief forming layer obtained above is gently cast so as not to flow out of the spacer (frame), and is kept in an oven at 90 ° C. for 3 hours. After drying, a recording layer having a thickness of about 1 mm was provided to produce a relief sheet.
The recording layer of the obtained relief sheet was heated at 80 ° C. for 3 hours and further at 100 ° C. for 3 hours to thermally crosslink the recording layer.
After the adhesive composition was applied to the relief sheet obtained by thermal crosslinking under the conditions described in Table 1, a 2.5 mm thick PET support was laminated with a nip roller, and 20 seconds later from the PET support side. The adhesive was cured with the exposure amount shown in Table 1 with a UV exposure machine (UV exposure machine ECS-151U metal halide lamp manufactured by Igraphic Co., Ltd., 1,500 mJ / cm ² 14 sec exposure) to prepare relief printing plate precursors. The peel force and in-plane flatness of each produced relief printing plate precursor were measured as follows. The evaluation results are summarized in Table 1.

<Evaluation of flatness of printing plate>
1. Film thickness flatness evaluation The film thickness of the obtained relief printing plate precursor was measured in 2 cm increments, and a value obtained by subtracting the film thickness minimum value (MAX value) from the film thickness maximum value (MAX value) was calculated. The smaller the value, the better the flatness.
2. Curl Evaluation The obtained relief printing plate precursor was cut into a 10 cm × 10 cm square shape, and as shown in FIG. 2, the raised height H when the cut relief printing plate precursor 100 was placed on the smooth surface 102 was measured. . The direction in which the relief printing plate precursor 100 is placed on the smooth surface 102 may be any direction in which H can be measured. The smaller the value of H, the better the flatness.

<Adhesion evaluation>
The obtained relief printing plate precursor was cut to a width of 3 cm, and then a part of the PET support and the recording layer was peeled off, and then 180 ° with respect to the support at a peeling rate of 50 mm / min with a Tensilon measuring instrument. The peel strength was measured. The greater the peel force, the better the adhesion.

10: Manufacturing apparatus for relief printing plate precursor 12: Recording layer 12a: Surface (air surface) facing the surface on the substrate side in the layer forming step of recording layer 12
12b: Surface of substrate side in recording layer 12 forming step 14: Recording layer roller 16: Conveying means 18: Adhesive applying means 20: Adhesive layer 22: Support roller 24: Support 26, 28: Nip roller 30 : UV irradiation means 32: Relief printing plate precursor 100: Relief printing plate precursor 102: Smooth surface H: Lifting height from smooth surface 102

Claims (13)

A layer forming step of forming a recording layer on the substrate;
A bonding step in which a photocurable adhesive is applied to the surface of the recording layer facing the substrate side in the layer forming step and bonded to a support; and
An adhesive step of curing the photocurable adhesive with light to bond the recording layer and the support,
The photocurable adhesive contains a (meth) acrylate compound having a hydroxyl group, a (meth) acrylate compound not having a hydroxyl group, and a photopolymerization initiator, and manufacturing a relief printing plate precursor for laser engraving Method.   The method for producing a relief printing plate precursor for laser engraving according to claim 1, wherein the recording layer has a thickness of 0.5 to 10 mm.   The relief printing for laser engraving according to claim 1 or 2, wherein the photo-curable adhesive comprises only a (meth) acrylate compound having a hydroxyl group, a (meth) acrylate compound not having a hydroxyl group, and a photopolymerization initiator. A method for producing an original plate.   The production of the relief printing plate precursor for laser engraving according to any one of claims 1 to 3, further comprising a protective step of forming a peelable protective layer on the substrate side surface in the layer forming step of the recording layer. Method.   The method for producing a relief printing plate precursor for laser engraving according to claim 1, wherein the recording layer contains a binder polymer and a photothermal conversion agent.   The method for producing a relief printing plate precursor for laser engraving according to claim 5, wherein the photothermal conversion agent contains carbon black.   The method for producing a relief printing plate precursor for laser engraving according to claim 1, wherein the recording layer has a siloxane bond.   The said layer formation process is a process of forming the recording layer which consists of a resin composition containing a binder polymer, a photothermal conversion agent, and a reactive silane compound on a base material. A method for producing a relief printing plate precursor for laser engraving as described in the paragraph.   The method for producing a relief printing plate precursor for laser engraving according to claim 8, comprising a crosslinking step in which the recording layer is thermally crosslinked between the layer forming step and the bonding step. A relief printing plate precursor for laser engraving, which is obtained by the production method according to claim 1. A relief process comprising: engraving a laser beam on the recording layer of the relief printing plate precursor for laser engraving obtained by the production method according to claim 1 to form a relief layer. How to make a printing plate.   The plate-making method of the relief printing plate of Claim 11 which engraves with the semiconductor laser with a fiber of wavelength 700-1300nm in the said engraving process. A relief printing plate having a relief layer produced by the plate making method of a relief printing plate according to claim 11 or 12.

Images